Conventionally, there is no technique that enables to monitor safety of a machine in real time and a technique that enables to reevaluate a risk for a safety programmable controller (PLC) using a safety network based on an actual response time of the network is disclosed (see Patent Literature 1).
In the conventional technique, an object is to reevaluate a safe distance between a machine and a safety sensor or a switch based on the actual response time of the safety network on the premise that the response time changes according to usage conditions. This enables visualization of the risk and prevention measures thereof.